Newbie looking to start putting on some weight

I am a college students, always busy with studying and doing other things. People tell me I should go do some work out and sport, but I always seem to have no time.

Well, I am graduating in May, and I think it is time for me to actually do something about my body. I am a very small guy (108 lbs, 5' 4") and I am not expecting to gain any height (lol).... I just want to put on some weight as a whole.

I found myself clueless as to how to start - like what kind of exercise I should do, how often, and what I should eat etc. Do you guys know any good resource that I can read up or guide lines to follow? Some personal experience would be great!